Four years ago, Jean Lazarus converted her basement in south Minneapolis into a mini mushroom farm. Today, she sells the food she grows at farmers markets around the Twin Cities. “My son had gone through a phase of being fascinated with all things mushrooms,” Lazarus said. “And so he taught me everything about growing them. He was 17 or 18.” Lazarus is just one of many vendors selling locally grown food at farmers markets in the Twin Cities thi…